This study was a randomized, masked, placebo-controlled trial, the purpose of which was to examine whether phenobarbital administered antenatally to pregnant women 24 to 33 weeks gestation reduces the incidence and severity of intraventricullar hemorrhage, reduces mortality and reduces the incidence of neurodevelopmental sequelae in preterm neonates. Infants <34 weeks gestation at delivery had a head ultrasound at 3-5 days of age, 10-14 days of age and at 36-42 weeks post conceptional age. All surviving neonates < 34 weeks gestation at delivery are enrolled in a follow-up program and will have neurodevelopmental information collected at 18 months of age.